Audi puts 305bhp TT concept on a diet

This is the Audi TT Ultra Quattro Concept, and it is aiming for a spot on the cover of a men's fitness magazine. This is because in preparation for its debut at the upcoming Worthersee show, it has shed some 300kg.

Three hundred kilos. Using the obligatory Other Things That Are Really Heavy analogy, that's the weight of a tiger. Or around three baby elephants. Or a couple of rotund auto enthusiasts.

The body structure has had another 43kg removed, while use of carbon-fibre reinforced polymer in the rear end, centre tunnel, B-pillars and roof helps achieve an overall 100kg saving

Why? Because Audi wants the world to know it can use a clever mix of materials to make its production cars less flabby, and more chiseled. This TT then, with its four-wheel-drive system, weighs just 1,111kg, will hit 0-100kph in 4.2 seconds (quicker than an Audi TT RS Plus and V8 R8) and top out at 278kph.

Next, the body structure of the TT Ultra has had another 43kg removed, while use of carbon-fibre reinforced polymer (CFRP) in the rear end, centre tunnel, B-pillars and roof helps achieve an overall 100kg saving. The brakes are ceramic - with aluminium calipers - there's a titanium exhaust system with a single tailpipe, and CFRP wheels with aluminium spokes that shed a further 20kg.

The steel in the coil springs has been replaced with fiberglass-reinforced polymer, using science and technology that sits outside TopGear's usual remit of Fix It With A Hammer (long glass fibres are twisted together, ‘impregnated' with epoxy resin, with additional fibres wrapped around the core at alternating angles). Overall, you're talking a 40 per cent weight reduction.

Then there's the small matter of jiggling the remaining weight around to keep the distribution in a place aforementioned auto enthusiasts will enjoy (ie, the middle). The lithium-ion battery weighs just 4kg and sits under the driver's seat.

Speaking of the seats, the TT Ultra gets the same FRP buckets used in the R8 GT (that save 22kg), the rear bench has been binned in favour of a cross-brace, and there are CFRP elements in the roof, flanks and tailgate, as well as the inside trim.

All this weight reduction however, must have been painful, so, the engineers were allowed to indulge their concept sides a touch by fitting a ruddy big wing. Yet even this is made from a combination of milled aluminium and carbon fibre.

"Work on the deployment of these materials," says Audi, "could conceivably inform the development of future low-volume Audi model series."

So there we have it - Audi adhering to Colin Chapman's oft-quoted maxim of ‘adding lightness'. It's roughly the same weight as a diesel Fiesta, for crying out loud. Reckon Audi should have just bunged in the V10 from the R8 and slapped on a new sticker instead, or do you like this Slim Fast philosophy?